KERMANSHAH, Iran - In what is being called the world’s deadliest earthquake this year, a 7.3-magnitude earthquake that shook the northern border region between Iran and Iraq, killed over 406 people and left thousands of others injured.

According to officials, over 7,000 people have suffered injuries in the quake and in several provinces, a search for survivors is ongoing.

The U.S. Geological Survey (USGS) said that the quake struck at 21:18 local time (18:18 GMT) about 30 km south-west of Halabja, near the north-eastern border with Iran.

According to officials, the earthquake struck at a relatively shallow depth of 23.2 km, and tremors were felt in Turkey, Israel and Kuwait.

As per UN estimates, about 1.8 million people live within 100km of the epicentre.

Iran’s western Kermanshah province recorded the highest casualty count, while nine more deaths were reported in Iraq, where residents fled from their homes into the streets in the capital, Baghdad.

An emergency official was quoted as saying in the Iran state news agency that 6,603 people were injured in the country.

Emergency services chief Pir Hossein Koolivand said that most of the victims were in the town of Sarpol-e Zahab, about 15km (10 miles) from the border.

State TV also said that the town's main hospital was severely damaged, even as hundreds of wounded struggled to find appropriate treatment.

According to an aid agency, 70,000 people are now in need of shelter after the devastating earthquake.

Officials explained that several homes in the predominantly Kurdish mountainous area are made of mud bricks and are vulnerable to quakes as large as the one experienced on Sunday.

A number of tall buildings collapsed to rubble in Sarpol-e Zahab city, that houses 85,000 people.

This forced many people to spend the night outdoors in freezing conditions and in the day, landslides hampered work being carried out by rescue teams.

Iran's emergency services chief Pir Hossein Koolivand said it was “difficult to send rescue teams to the villages because the roads have been cut off... there have been landslides.”

On Monday morning, Iran’s Supreme Leader Ayatollah Ali Khamenei offered his condolences and urged rescuers and all government agencies to do all they could to help those affected.

In Iraq, the most extensive damage was witnessed in the Darbandikhan town in the Kurdistan Region.

Kurdish Health Minister Rekawt Hama Rasheed said in statement, "The situation there is very critical.”

Meanwhile, Yaseen Abbas of the Iraqi Red Crescent Society said that 425 people had been wounded in the Iraqi Kurdistan region, where Turkey has already delivered aid.

Turkish Prime Minister Binali Yildirim said his country has immediately taken action to provide medical and food aid to northern Iraq.

Kerem Kinik, Turkish Red Crescent’s vice president added that 33 aid trucks were en route to Iraq’s city of Sulaimaniyah from the Habur border crossing, carrying 3,000 tents and heaters, 10,000 beds and blankets as well as food.

Mojtaba Nikkerdar, the deputy governor of Iran’s Kermanshah province said, “We are in the process of setting up three emergency relief camps.”

According to reports, Pakistan’s government too has extended its deepest condolences for the loss of life and injuries suffered by “our Iranian and Iraqi brethren.”

Pakistan’s Foreign Minister Khawaja Muhammad Asif said Pakistanis’ “thoughts and prayers are with the Iranian and Iraqi brothers who lost their lives in this tragic calamity and we pray for the speedy recovery of the injured.”

Soon after the quake, Iranian social media was flooded with images and videos of panic-stricken people running out of their homes and officials noted that the country experienced at least 50 aftershocks.

The Indian Prime Minister Narendra Modi, who is at the ASEAN summit in Manila, offered his condolences and said on Twitter, “My thoughts are with all those who have lost their loved ones in the tragic earthquake that has affected parts of Iran and Iraq. I pray that those injured recover at the earliest.”

Iran, which has experienced some very big tremors in the past, witnessed its previous devastating earthquake, a massive 6.6-magnitude one, in 2003.

The quake destroyed the historic city of Bam in south-east Iran, killing 26,000 people.

According to estimates, Sunday's quake is the deadliest to hit Iran since 2012 - however, it is only the sixth earthquake of magnitude 7.0 or more in 2017.

The clash between the Arabia and Eurasia tectonic plates in the region is the main cause of earthquake and each year, the Arabia tectonic plate pushes north by a couple of centimetres.

Geological agencies explained that in the south-east of the country, the Arabia plate is actually pushing under the Eurasia plate, but in the north-west these great slabs rub directly against each other. The Zagros mountains are a result of all this compression.